Optimizing Matrix Viscosity to Enhance Composite Performance

Optimizing matrix viscosity is crucial for enhancing the mechanical performance of fiber-reinforced composites.

The performance of fiber-reinforced composites strongly depends on matrix viscosity, which significantly affects key mechanical properties, including bending strength, impact resistance, and creep behavior. Industries such as aerospace, automotive, and construction must focus on optimizing this parameter to enhance the quality and reliability of their materials.

You can also read: Evaluating Fatigue Performance of 3D-Printed Carbon Fiber Composites.

Key Insights on Matrix Viscosity and Composite Behavior

Recent research demonstrates that adjusting matrix viscosity directly impacts composite properties, particularly when mixing epoxy resins with diluents like BDDGE. Using vacuum-assisted resin infusion (VARI), researchers fabricated composites and tested viscosities of 220, 205, 180, and 165 mPa·s by varying diluent concentrations. The findings reveal that balancing viscosity is crucial to improving performance, while excessive diluent addition can degrade mechanical properties.

Bending Properties: Achieving Optimal Strength

Matrix viscosity is vital in improving bending strength and modulus, as composites at 180 mPa·s showed the best results. Researchers found that optimal viscosity increased bending strength by 19%, creating a robust three-dimensional network structure.

However, excessive diluent addition increased flexible chain segments, weakening stiffness and reducing structural integrity. Manufacturers must carefully control viscosity to optimize bending properties while avoiding flexibility that leads to premature failure under applied loads.

Impact Resistance: Enhancing Toughness

Composites designed with 180 mPa·s viscosity demonstrated the highest impact resistance, absorbing 32% more energy compared to those at higher viscosities. This improvement occurred because reduced viscosity strengthened the fiber-matrix bond and minimized delamination during dynamic loads.

Furthermore, the study revealed that lower viscosity levels below 180 mPa·s caused excessive flexibility, leading to weaker impact resistance. Therefore, maintaining viscosity close to this threshold ensures durability in applications requiring toughness under sudden impacts.

Creep Behavior: Balancing Long-Term Stability

Maintaining long-term stability under stress, known as creep resistance, is another property affected by matrix viscosity. Composites with a viscosity of 165 mPa·s demonstrated superior creep resistance, with minimal deformation over extended periods.

However, while lower viscosity improved creep behavior, it reduced stiffness and weakened fiber-matrix interactions. Manufacturers must assess application-specific requirements when selecting viscosity levels, balancing creep resistance with stiffness to meet performance needs.

Actionable Takeaways for Manufacturers

1. Prioritize Optimal Viscosity: Maintain matrix viscosity between 180–185.3 mPa·s to balance bending strength, impact toughness, and creep resistance effectively.
2. Control Diluent Ratios: Avoid excessive diluent additions, which increase flexibility and compromise overall material stiffness and mechanical strength.
3. Leverage Predictive Models: Use mathematical models to predict mechanical outcomes, reducing time spent on trial-and-error during the production process.

Main Conclusions

Matrix viscosity directly influences the mechanical performance of fiber-reinforced composites, impacting their strength, toughness, and stability. By optimizing viscosity levels, manufacturers can produce high-performance materials tailored for demanding applications across multiple industries. Ultimately, this research provides actionable insights for improving processes and maximizing the potential of fiber-reinforced composites.

To read the full paper click here.